PET-MRI is a hybrid imaging modality that acquires both an MRI and a PET scan of either the whole body (head to toe), partial whole body (head to mid-thigh) and/or specific regions of interest (ex: chest, abdomen, pelvis) at the same time.
For the PET portion of the study, a small amount of radioactive material is injected into the body. The type of radioactive material depends on the organ or tissue being studied. Once the injection is completed, the patient will wait approximately 60 minutes in a quiet area with limited movement to allow the body to absorb the radioactivity. More of the radiotracer material will accumulate in the cells with higher chemical activity, which generally corresponds to the areas of disease.
For the MRI portion, magnetic fields and radio frequency bursts will move the molecules in the patient's body out of their normal alignment or their normal spinning pattern. As the molecules return to their natural positions, the machine records that activity and uses the information to create detailed images of the organs, tissues and other structures inside the body.
The images acquired from the PET-MRI scan are then processed and looked at by a physician to detect and characterize the disease in question.